In general, conventional back-up batteries (e.g., back-up battery systems used for wireless or other large format back-up systems) have the strength of being low cost and the weaknesses of having a low rate and being slow to charge and easily damaged by high rate demand or charge. Thus, conventional back-up battery systems are best utilized when power is off for extended time, and do not function well for load leveling.
What is needed is a new back-up battery system that takes advantage of the strengths of conventional back-up batteries and functions well for load leveling.